// header / 所有分类 / 点击动画
var all_class_h2 = $(".header_bottom .all_class h2"),
    all_class_ul = $(".header_bottom .all_class ul");
all_class_h2.on("click",function(){
  if(all_class_ul.css("display") == "none"){
    all_class_ul.slideDown(500);
  }else{
    all_class_ul.slideUp(500);
  }
})